Assessment of manoeuvring performance of large tankers in restricted waterways: a real-time simulation approach

During the past 30 years there has been a steady growth in the size and number of ships that use the Strait of Istanbul (Bosporus) which is one of the most hazardous, crowded, difficult and potentially dangerous waterways in the world. There have been over 200 accidents over the past decade resulting in loss of life and serious damage to the environment. This paper presents the results of a real-time ship manoeuvring simulation study investigating the manoeuvring performance of large tankers in the Bosporus. The study was conducted with a ship manoeuvring simulator which is capable of subjecting a given hull form to any combination of environmental conditions, i.e. wind, current and wave drift forces. The results indicate that when realistic environmental conditions are taken into account the size of ships which can navigate safely in compliance with the traffic separation lanes is limited.     

凡纳滨对虾(Litopenaeus vannamei)即食虾仁在常温保藏中的货架期预测及品质分析

采用化学分析、质构检测及动力学模型建立等方法, 对凡纳滨对虾(Litopenaeus vannamei)即食虾仁在常温保藏中的细菌总数、TVB-N值、pH值、质构特性、色差值及感官评价等参数进行测定。以挥发性盐基氮TVB-N作为货架寿命的关键指示因子, 利用Arrhenius法预测常温流通高水分即食调味虾仁的货架寿命。计算结果Ea为65.26kJ/mol, k0为6.04×109, 进一步推算得到在20℃和25℃常温流通条件下, 即食虾仁产品的货架期为148.61d和94.1d。在25℃保藏3个月的虾仁虽在细菌总数、TVB-N值、pH值、感官评分、质构、色差值等方面均发生了一些变化, 但都在安全范围之内, 不影响其食用价值。本研究为常温流通的即食虾仁产品开发奠定了理论基础。     

实现APPLE一Ⅱ机汉字通讯的一种方法

本文提出了实现Apple-Ⅱ机汉字通讯的一种方法,即通过调用机器语言子程序自动修改与生成BASIC语句,利用BASIC程序的汉字功能打印汉字。用这种方法可以很容易地把廉价的Apple-Ⅱ机改造为中英文通讯终端。     

Watchsys系统在广西气象局省级中心机房综合管理的应用

通引入Watchsys系统,对省级中心机房配电、空调、安防、消防等设备进行综合管理,通过对各项参数的测试和一年多来的使用,系统正确报警率为100％,没有出现错、漏报.系统建成使用后有效提高机房的综合管理效率和应急反应速度,确保机房设备的安全和正常运行.     

An approach to folding kinematics from the analysis of folded oblique surfaces

Two-dimensional analysis of folded surfaces oblique to the mechanical layering can shed light on the kinematic mechanisms that operated during the development of folds. A new version of the program ‘FoldModeler’, developed in the Mathematica™ environment, is used to obtain the deformed configuration of an initial pattern of oblique surfaces deformed by any combination of the most common kinematic folding mechanisms: flexural flow, tangential longitudinal strain, with or without area change and heterogeneous simple shear. The layer can also undergo any form of homogeneous strain at any moment of the folding process. The outputs of the program provide complete information about the strain distribution in the folded layer that includes graphs of the angle between the oblique surfaces as a function of the inclination of the layering through the fold. These graphs can be very useful to discriminate between the mechanisms that operate in the development of natural folds, and they have been obtained and discussed for the most common combinations of strain patterns. The program is applied to obtain theoretical folds that give a good fit of some natural examples of folded oblique surfaces.     

Subsidence prediction in shallow room and pillar mines

Summary A mathematical model has been developed utilizing the relative flexural strength of the strata overlying a coal seam to predict the vulnerability of shallow room and pillar mined areas to subsidence. The model assumes the failure of the immediate roof as the precursor of a subsidence event in shallow room and pillar mines. After the roof fails, either a sink hole subsidence event develops if the unconsolidated material is thin and dry; or a subsidence trough forms if the unconsolidated material is thick and wet. The model relates the Missavage number (Mn), which is dependent only on the stratigraphy and rock strength, to the extraction number, which is dependent only on the extraction ratio and maximum span of the opening. A high correlation coefficient (r=0.78) betweenMn and the extraction number for 27 subsidence events in a southern Illinois mine showed potential for using this model to delineate areas more vulnerable to subsidence. The developed and validated model was then subjected to a blind test on a 12.9 square kilometer area of an Illinois Coal Basin mine. The model successfully predicted 10 out of 12 subsidence events in the blind half of the study area and two of three additional subsidence events in the known half of the study area.     

DDW－3型钻探微机监测系统绳索取心钻进应用试验

本文简述了ＤＤＷ－３型钻探微机多功能监测系统的组成、主要功能、特点、钻探参数测试范围及精度指标。讨论了该系统在豫西小秦岭金矿田绳索取心钻进应用试验效果及前景。     

A two-dimensional kinematic model for predicting muckpile shape in bench blasting

Summary Most existing models of blasting are stress-based and involve many fundamental parameters difficult or impossible to measure in practice. Even a single prediction with such models takes large quantities of computer time, so that calibration becomes a major impediment to their practical use.The model in this paper is based on a simple kinematic approach to modelling muckpile formation. This has the advantage of relative simplicity, while still reflecting the essence of the blasting displacement process. Because of the simple implementation, the model can be calibrated against field data in a straightforward manner and then used for predictions at the same site. The inputs to the model are simply the blast design parameters. The output of the model is a muckpile cross-section, within which contours of diggability or distribution of materials can also be calculated. Case studies have shown that, provided the model is calibrated to the site condition, it will give accurate predictions for altered blast designs.     

计算机在孢粉学中的应用现状与前景

计算机在孢粉学中的应用现状与前景姜钦华（北京大学地质系１００８７１）关键词孢粉学，计算机，数据分析与处理计算机作为一门新技术已逐步渗透到各个学科，并且发挥着越来越大的作用。西方孢粉学家早在７０年代初就开始尝试应用计算机来处理孢粉分析的数据（如Ｓｑｕｉ...     

A review of: “National Transfer Format,Release 1.0, January, 1987.” By THE WORKING PARTY TO PRODUCE NATIONAL STANDARDS FOR THE TRANSFER OF NATIONAL DIGITAL MAP DATA. (Southampton: The NTF Secretariat,Ordnance Survey, 1987. [Pp. 191: appendices and looseleaf annex.]

Metonymically used location names (toponyms) refer to other, related entities and thus possess a meaning different from their literal, geographic sense. Metonymic uses are to be treated differently to improve the performance of geographic information retrieval (GIR). Statistics on toponym senses show that 75.06% of all location names are used in their literal sense, 17.05% are used metonymically, and 7.89% have a mixed sense. This article presents a method for disambiguating location names in texts between literal and metonymic senses, based on shallow features.

The evaluation of this method is two‐fold. First, we use a memory‐based learner (TiMBL) to train a classifier and determine standard evaluation measures such as F‐score and accuracy. The classifier achieved an F‐score of 0.842 and an accuracy of 0.846 for identifying toponym senses in a subset of the CoNLL (Conference on Natural Language Learning) data.

Second, we perform retrieval experiments based on the GeoCLEF data (newspaper article corpus and queries) from 2005 and 2006. We compare searching location names in a database index containing both their literal and metonymic senses with searching in an index containing their literal senses only. Evaluation results indicate that removing metonymic senses from the index yields a higher mean average precision (MAP) for GIR. In total, we observed a significant gain in MAP: an increase from 0.0704 to 0.0715 MAP for the GeoCLEF 2005 data, and an increase from 0.1944 to 0.2100 MAP for the GeoCLEF 2006 data.